Coaxial cable is being deployed on a widespread basis in order to carry signals for communications networks, e.g., CATV and computer networks. All types of coaxial cable must at some point be connected to network equipment ports. In general, it has proven difficult to correctly make such connections without requiring labor intensive effort by highly skilled technicians. Moreover, even if careful attention is paid during installation, there still can be installation errors, which, in turn, can moderately to several affect signal quality.
These generalized installation problems are likewise encountered with respect to spiral corrugated coaxial cable (i.e., cable that is often referred to in the art as “Superflex” cable), which, however, also poses its own set of unique issues. Spiral corrugated coaxial cable is a special type of coaxial cable that is utilized in situations where it is necessary for the cable to be rotation resistant and/or highly flexible.
Unlike standard coaxial cable, the spiral corrugated variety has an irregular outer surface. That, in turn, makes it difficult for those in the art to design connectors or connection techniques for engagement of the spiral corrugated coaxial cable in a manner that provides a high degree of mechanical stability, electrical shielding and environmental sealing yet that also is not physically damaging the irregular outer surface of the cable.
In an effort to overcome this difficulty, some in the art have opted to utilize a soldering technique in order to join spiral corrugated coaxial cable to a connector. Although this methodology generally ensures that reliable mechanical and electrical connections are achieved, it also necessitates usage of highly specialized, unwieldy soldering equipment as well as the dedication of trained manpower to perform the soldering. Consequently, soldering has emerged as a realistic option only for assembling factory-made jumpers, not for joining spiral corrugated coaxial cable to connectors in a field installation setting.
Another current approach to overcoming this difficulty is to utilize a connector that makes contact with the conductive outer wall of the spiral corrugated coaxial cable through a thread-like internal protrusion shaped to substantially match the pitch and groove width of the corrugations of the spiral corrugated coaxial cable. The connector is screwed onto the cable, which is then drawn tight against the internal thread protrusion as it bottoms on a stop within the connector. The spiral corrugated coaxial cable is then held in place within the connector through use of a secondary clamping device, which clamps onto an exterior portion of the cable (e.g., the corrugated outer wall, the outer jacket).
This approach has several benefits, such as the fact that it can be utilized in either a factory or field installation setting. However, these benefits are more than overshadowed by various drawbacks, most notably the unreliability of the technique. For example, the shielding that is achieved by contact forces created between the thread protrusion of the connector and the outer wall of the spiral corrugated coaxial cable can degrade over time. Moreover, in order for the thread protrusion to be installable on the spiral corrugated coaxial cable there must be some clearance between it and the cable, and the only interference between the cable and the connector exists as a result of contact force generated by bottoming the cable in the connector against the course pitch threads of the cable and protrusion. However, the contact force can become relaxed over time, due to one or more common conditions such as temperature fluctuations, vibrations, and flexure of the cable relative to the connector. And if the contact force becomes relaxed, then the necessary interference is negated and, in turn, the connection between the cable and the connector is lost.
Thus, there is a need for a connector for spiral corrugated coaxial cables that is simple to install, is reliably effective at establishing and maintaining both electrical and mechanical engagement to the spiral corrugated coaxial cable, and that does not suffer from the aforementioned problems that have plagued previous connectors and connection techniques in the art.